144 ESSAYS AND OBSERVATIONS 



SLB, that Is, equal to the angle KBD ; and 

 therefore, from a known property of the 

 ellipfe, BD is a tangent to the ellipfe at the 



point Bj and therefore [Pro/». 2.]] the feftor 

 ACB is greater than the fedor ASE> and lefs 

 than the fedtor ASF : but, becaufe G is the 

 place of the planet, the area of the ellipfe 

 will be to the fedor ASG as the periodic 

 time of the planet round the fun is to the 

 time elapfed fince the planet pafTed thro' the 

 point A, that is, as the area of the ellipfe to 

 the fedor ACB ; therefore the feftor ASG 

 is equal to the fedlor ACB ; and therefore 

 the fedlor ASG is greater than the fedtor 

 ASE, and lefs than the fedlor ASF ; there- 

 fore the line SG falls between the lines SE, 

 SF; and therefore G, the place of the planet, 

 is between the points E, F ; therefore the 

 planet has paiTed the point E, but not come 

 to the point F. 



Art. 



